The invention relates to a spring strut support bearing.
Spring strut support bearings (also known as suspension turret webs) are generally known and, for example, form a part of a front suspension in a motor vehicle.
The object of the present invention is to further develop a suspension turret web in such a way that extreme deflections of the inner ring in the direction of the introduced vibrations are limited in relation to the outer ring of a top bearing which forms a component of the spring strut. A further object is that undesirably high shearing stresses in the elastic spring element which connects the inner and outer rings of the top bearing be prevented, and that because of this, the suspension turret web exhibits uniformly good working properties during a longer service life.
To achieve the objective, a suspension turret web is provided which includes a top bearing that is able to be affixed by its inner ring to the front end, the end of a piston rod of a shock absorber facing a vehicle body. The inner ring is surrounded by an outer ring with radial clearance. At least one elastic spring element made of rubber-elastic material is arranged in the gap formed by the clearance, and the outer ring is disposed in a stationary manner with respect to the vehicle body. The inner ring has on each of its two end faces at least one elastically flexible stop buffer for limiting extreme deflection movements in the moving direction of the shock absorber, and the stop buffers each have the capability of being brought into contact with counter stop faces. The above-described embodiment ensures the prevention of undesirably high shearing stresses within the elastic spring element which reduce its service life, because the deflection movement of the inner ring relative to the outer ring is limited by the elastically flexible stop buffers. In this context, the counter stop faces are fixedly joined to the vehicle body. Parts which are fixedly joined to the vehicle body, thus, for example, plates which are bolted or welded to the vehicle body, also belong to the vehicle body within the framework of the present invention. The stop buffers always contact their counter stop faces when low-frequency, large-amplitude vibrations are introduced into the shock absorber, for example, when the wheel runs over the curb.
The top bearing can be produced simply and cost-effectively by forming the stop buffers and the elastic spring element in one piece and of the same material. The stop buffers and the elastic spring element are injected in one shared operation into a tool cavity in which the inner ring and the outer ring of the top bearing are already inserted. Following the injection of the rubber-elastic material, this material hardens gradually and clutches permanently with claw-like fixation to the surfaces of the inner and outer rings.
Another embodiment offers the possibility of producing the stop buffers separately and connecting them frictionally and/or with form locking to the respective end face of the inner ring. An advantage in this case is that the stop buffers can be adapted particularly well to the respective conditions of the specific application, irrespective of the material from which the elastic spring element is made. For example, the stop buffers can be mounted with adhesive on the end faces of the inner ring or can have the ability to snap into undercut, e.g., dovetailed recesses, of the inner ring.
A comparatively more durable, form-locking connection can be achieved in that the inner ring has at least one opening extending essentially in the axial direction from end face to end face, and the opening is penetrated by material of the stop buffers. Such an embodiment is only useful when the rubber-elastic material is injected into a tool cavity and subsequently vulcanized between the inner ring and outer ring.
Stop buffers made of a cellular polyurethane have particularly advantageous working properties. Compared to other materials, cellular polyurethane has the advantage that the damping capacity increases relatively with the increase in amplitude, and the dynamic hardening is generally not so high compared to elastomers.
The stop buffers can be formed on each side of the inner ring by, in each case, at least three lug cams uniformly distributed in the circumferential direction. The form of the lug cams is preferably such that a progressively rising spring tension results as the spring deflection path increases. This ensures that the stop buffers contact the counter stop faces gently at first, e.g., to prevent shaking and sharp noises, and a stronger bracing of the two parts against each other only results as the spring deflection path increases.
The outer ring can be stationary mounted in an essentially cup-shaped flange, the flange and the vehicle body being fixedly joined. Such an embodiment is advantageous with a view to producing suspension turret webs in the unitized construction system. Variously configured flanges offer the possibility of adapting the suspension turret web to the respective installation situation.